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Gatto L, Fernando A, Patel M, Yeung A, Ackland DC. Subacromial contact after acromioplasty in the rotator cuff deficient shoulder. J Orthop Res 2024; 42:588-597. [PMID: 37812185 DOI: 10.1002/jor.25717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 09/24/2023] [Accepted: 10/05/2023] [Indexed: 10/10/2023]
Abstract
Subacromial impingement (SAI) is associated with shoulder pain and dysfunction and is exacerbated by rotator cuff tears; however, the role of acromioplasty in mitigating subacromial contact in the rotator cuff deficient shoulder remains debated. This study aimed to quantify the influence of isolated and combined tears involving the supraspinatus on subacromial contact during abduction; and second, to evaluate the influence of acromioplasty on joint space size and subacromial contact under these pathological conditions. Eight fresh-frozen human cadaveric upper limbs were mounted to a computer-controlled testing apparatus that simulated joint motion by simulated force application. Shoulder abduction was performed while three-dimensional joint kinematics was measured using an optoelectronic system, and subacromial contact evaluated using a digital pressure sensor secured to the inferior acromion. Testing was performed after an isolated tear to the supraspinatus, as well as tears involving the subscapularis and infraspinatus-teres minor, both before and after acromioplasty. Rotator cuff tears significantly increased peak subacromial pressure (p < 0.001), average subacromial pressure (p = 0.001), and contact force (p = 0.034) relative to those in the intact shoulder. Following acromioplasty, significantly lower peak subacromial contact pressure, force and area were observed for all rotator cuff tears involving the supraspinatus at 30° of abduction (p < 0.05). Acromioplasty predominantly reduces acromion thickness anteriorly thereby reducing subacromial contact in the rotator cuff deficient shoulder, particularly in early to mid-abduction where superior glenohumeral joint shear force potential is large. These findings provide a biomechanical basis for acromioplasty as an intervention for SAI syndrome and as an adjunct to rotator cuff repairs.
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Affiliation(s)
- Laura Gatto
- Department of Biomedical Engineering, University of Melbourne, Parkville, Victoria, Australia
| | - Ashen Fernando
- Department of Biomedical Engineering, University of Melbourne, Parkville, Victoria, Australia
| | - Minoo Patel
- Department of Orthopaedic Surgery, Epworth Healthcare, Richmond, Victoria, Australia
- Department of Anatomy and Cell Biology, University of Melbourne, Parkville, Victoria, Australia
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Victoria, Australia
| | - Angus Yeung
- Department of Biomedical Engineering, University of Melbourne, Parkville, Victoria, Australia
| | - David C Ackland
- Department of Biomedical Engineering, University of Melbourne, Parkville, Victoria, Australia
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Lee D, Lee J, Oh JH, Shin CS. Effect of subscapularis repair on joint contact forces based on degree of posterior-superior rotator cuff tear severity in reverse shoulder arthroplasty. Front Bioeng Biotechnol 2023; 11:1229646. [PMID: 38130822 PMCID: PMC10733495 DOI: 10.3389/fbioe.2023.1229646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 11/27/2023] [Indexed: 12/23/2023] Open
Abstract
Massive irreparable rotator cuff tears (RCTs) affect the clinical outcomes of reverse shoulder arthroplasty (RSA). However, the effects of subscapularis repair on the outcomes of RSA, based on the degree of posterior-superior RCTs, are unclear. This study aimed to examine the effect of subscapularis repair on three-dimensional joint contact forces (JCFs) based on the degree of posterior-superior RCT severity in RSA. Ten human in vivo experimental data were used as input to the musculoskeletal model. A six-degrees-of-freedom (DOF) anatomical shoulder model was developed and validated against three-dimensional JCFs. The 6-DOF musculoskeletal shoulder model of RSA was then developed by importing the reverse shoulder implant into the validated anatomical shoulder model. Based on the various types of posterior-superior RCT severity, inverse dynamic simulations of subscapularis-torn and subscapularis-repaired models of RSA were performed: from isolated supraspinatus tears to partial or massive tears of the infraspinatus and teres minor. The intact rotator cuff model of RSA was also simulated for comparison with the different types of models. Our results showed that the more posterior-superior RCTs progressed in RSA, the more superior JCFs were observed at 90°, 105°, and 120° abduction in the subscapularis-torn model. However, subscapularis repair decreased the superior JCF at those angles sufficiently. In addition, the teres minor muscle-tendon force increased as infraspinatus bundle tears progressed in both the subscapularis-torn and -repaired models, in order to compensate for the reduced force during abduction. However, the teres minor muscle-tendon force was not as high as that of the infraspinatus muscle-tendon, which could result in muscle force imbalance between repaired subscapularis and teres minor. Therefore, our results suggest that repairing the subscapularis and the repairable infraspinatus during RSA can improve glenohumeral joint stability in the superior-inferior direction by restoring muscle force balance between the anterior cuff (i.e., subscapularis) and posterior cuff (i.e., infraspinatus and teres minor). The findings of this study can help clinician decide whether to repair the rotator cuff during RSA to enhance joint stability.
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Affiliation(s)
- Donghwan Lee
- Department of Mechanical Engineering, Sogang University, Seoul, Republic of Korea
| | - Jinkyu Lee
- Department of Rehabilitation Medicine, Seoul National University Hospital, Seoul, Republic of Korea
| | - Joo Han Oh
- Department of Orthopaedic Surgery, Seoul National University Bundang Hospital, Seongnam, Republic Korea
| | - Choongsoo S. Shin
- Department of Mechanical Engineering, Sogang University, Seoul, Republic of Korea
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Ernstbrunner L, Robinson DL, Huang Y, Wieser K, Hoy G, Ek ET, Ackland DC. The Influence of Glenoid Bone Loss and Graft Positioning on Graft and Cartilage Contact Pressures After the Latarjet Procedure. Am J Sports Med 2023; 51:2454-2464. [PMID: 37724693 DOI: 10.1177/03635465231179711] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 09/21/2023]
Abstract
BACKGROUND Glenohumeral joint contact loading before and after glenoid bone grafting for recurrent anterior instability remains poorly understood. PURPOSE To develop a computational model to evaluate the influence of glenoid bone loss and graft positioning on graft and cartilage contact pressures after the Latarjet procedure. STUDY DESIGN Controlled laboratory study. METHODS A finite element model of the shoulder was developed using kinematics, muscle and glenohumeral joint loading of 6 male participants. Muscle and joint forces at 90° of abduction and external rotation were calculated and employed in simulations of the native shoulder, as well as the shoulder with a Bankart lesion, 10% and 25% glenoid bone loss, and after the Latarjet procedure. RESULTS A Bankart lesion as well as glenoid bone loss of 10% and 25% significantly increased glenoid and humeral cartilage contact pressures compared with the native shoulder (P < .05). The Latarjet procedure did not significantly increase glenoid cartilage contact pressure. With 25% glenoid bone loss, the Latarjet procedure with a graft flush with the glenoid and the humerus positioned at the glenoid half-width resulted in significantly increased humeral cartilage contact pressure compared with that preoperatively (P = .023). Under the same condition, medializing the graft by 1 mm resulted in humeral cartilage contact pressure comparable with that preoperatively (P = .097). Graft lateralization by 1 mm resulted in significantly increased humeral cartilage contact pressure in both glenoid bone loss conditions (P < .05). CONCLUSION This modeling study showed that labral damage and greater glenoid bone loss significantly increased glenoid and humeral cartilage contact pressures in the shoulder. The Latarjet procedure may mitigate this to an extent, although glenoid and humeral contact loading was sensitive to graft placement. CLINICAL RELEVANCE The Latarjet procedure with a correctly positioned graft should not lead to increased glenohumeral joint contact loading. The present study suggests that lateral graft overhang should be avoided, and in the situation of large glenoid bone defects, slight medialization (ie, 1 mm) of the graft may help to mitigate glenohumeral joint contact overloading.
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Affiliation(s)
- Lukas Ernstbrunner
- Department of Orthopaedic Surgery, Royal Melbourne Hospital, Parkville, Victoria, Australia
- Department of Biomedical Engineering, University of Melbourne, Parkville, Victoria, Australia
- Melbourne Orthopaedic Group, Windsor, Victoria, Australia
| | - Dale L Robinson
- Department of Biomedical Engineering, University of Melbourne, Parkville, Victoria, Australia
| | - Yichen Huang
- Department of Biomedical Engineering, University of Melbourne, Parkville, Victoria, Australia
| | - Karl Wieser
- Department of Orthopedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Greg Hoy
- Melbourne Orthopaedic Group, Windsor, Victoria, Australia
| | - Eugene T Ek
- Melbourne Orthopaedic Group, Windsor, Victoria, Australia
| | - David C Ackland
- Department of Biomedical Engineering, University of Melbourne, Parkville, Victoria, Australia
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Lavaill M, Martelli S, Cutbush K, Gupta A, Kerr GK, Pivonka P. Latarjet's muscular alterations increase glenohumeral joint stability: A theoretical study. J Biomech 2023; 155:111639. [PMID: 37245383 DOI: 10.1016/j.jbiomech.2023.111639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 03/20/2023] [Accepted: 05/10/2023] [Indexed: 05/30/2023]
Abstract
The surgical Latarjet procedure aims to stabilise the glenohumeral joint following anterior dislocations. Despite restoring joint stability, the procedure introduces alterations of muscle paths which likely modify the shoulder dynamics. Currently, these altered muscular functions and their implications are unclear. Hence, this work aims to predict changes in muscle lever arms, muscle and joint forces following a Latarjet procedure by using a computational approach. Planar shoulder movements of ten participants were experimentally assessed. A validated upper-limb musculoskeletal model was utilised in two configurations, i.e., a baseline model, simulating normal joint, and a Latarjet model simulating its related muscular alterations. Muscle lever arms and differences in muscle and joint forces between models were derived from the experimental marker data and static optimisation technique. Lever arms of most altered muscles, hence their role, were substantially changed after Latarjet. Altered muscle forces varied by up to 15% of the body weight. Total glenohumeral joint force increased by up to 14% of the body weight after Latarjet, mostly due to increase in compression force. Our simulation indicated that the Latarjet muscular alterations lead to changes in the muscular recruitment and contribute to the stability of the glenohumeral joint by increasing compression force during planar motions.
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Affiliation(s)
- Maxence Lavaill
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, QLD, Australia; Queensland Unit for Advanced Shoulder Research, Brisbane, QLD, Australia.
| | - Saulo Martelli
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, QLD, Australia; Queensland Unit for Advanced Shoulder Research, Brisbane, QLD, Australia; Medical Device Research Institute, College of Science and Engineering, Flinders University, Tonsley, SA, Australia
| | - Kenneth Cutbush
- Queensland Unit for Advanced Shoulder Research, Brisbane, QLD, Australia; St Andrew's War Memorial Hospital, Brisbane, QLD, Australia; School of Medicine, University of Queensland, Brisbane, Australia
| | - Ashish Gupta
- Queensland Unit for Advanced Shoulder Research, Brisbane, QLD, Australia; Greenslopes Private Hospital, Brisbane, Australia
| | - Graham K Kerr
- Queensland Unit for Advanced Shoulder Research, Brisbane, QLD, Australia; Movement Neuroscience Group, School of Exercise & Nutrition Sciences, Queensland University of Technology, Brisbane, QLD, Australia
| | - Peter Pivonka
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, QLD, Australia; Queensland Unit for Advanced Shoulder Research, Brisbane, QLD, Australia
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Vopat ML, Peebles AM, Hanson JA, Powell SN, Mologne MS, Jildeh TR, Foster MJ, Eble SK, Millett PJ, Provencher CAPTMT. Impact of Prior Anterior Instability on Shoulder Arthroplasty Outcomes: A Systematic Review. JSES Int 2022; 6:874-883. [PMID: 36353431 PMCID: PMC9637700 DOI: 10.1016/j.jseint.2022.08.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Background Anterior shoulder instability (ASI) is a frequently encountered pathology. Patients with a history of ASI have an increased rate of developing glenohumeral osteoarthritis and becoming candidates for shoulder arthroplasty. This systematic review aims to synthesize outcomes for patients undergoing shoulder arthroplasty with a history of ASI. Methods A comprehensive literature review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) using PubMed, Embase, OVID Medline, Scopus, CINAHL, Web of Science, and Cochrane databases for studies evaluating the impact of prior ASI on total shoulder arthroplasty (TSA), reverse TSA, and/or hemiarthroplasty outcomes, with a minimum follow-up of 12 months. Studies were graded by level of evidence and data concerning patient demographics and outcomes were extracted. Results Sixteen articles met the inclusion criteria, including 596 patients (413 male, 181 female). The average age of the control and prior ASI groups were 57.5 and 57.0 years, respectively. Overall, 251 patients were treated operatively, 132 nonoperatively, and 213 were controls without a history of prior ASI. Shoulder arthroplasty techniques included TSA (436 shoulders), reverse TSA (130 shoulders), and hemiarthroplasty (14 shoulders). Prior anterior stabilization management included soft tissue repair, bony augmentation, and nonoperative treatment. Almost all studies reported no significant difference in subjective and functional arthroplasty outcomes between control and prior ASI groups, or between patients with prior ASI treated nonoperatively vs. surgically. Conclusion Shoulder arthroplasty in the setting of prior ASI results in improved subjective and functional outcome scores that are comparable to patients without a history of instability.
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Murali S, Elphingstone JW, Paul KD, Messner M, Frazier MB, Narducci CA, Phillips BM, Bass RZ, McGwin G, Brabston EW, Ponce BA, Momaya AM. Insurance status is not a predictor of rotator cuff tear magnitude. JSES Int 2022; 6:815-819. [PMID: 36081697 PMCID: PMC9446165 DOI: 10.1016/j.jseint.2022.05.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Background Rotator cuff tear (RCT) chronicity is an important factor in considering treatment options and outcomes for surgical repair. Many factors may contribute to delayed treatment, including timely access to care due to insurance status. The purpose of this study was to evaluate the relationship between the magnitude of RCT on presentation and insurance status. We hypothesize that publicly insured patients will have a greater incidence of chronic RCTs and shoulder pathology on initial presentation. Methods Retrospective chart review of patients undergoing RCT repair at an academic tertiary care institution from 2005 to 2019. Demographic data, including age, race, sex, and insurance carrier, were collected. Insurance carriers were categorized into public (Medicare and Medicaid) or private insurance coverage. Individual magnetic resonance imagings were then reviewed by a board-certified musculoskeletal radiologist for supraspinatus (SS), infraspinatus (IS), subscapularis, and biceps tendon tears, as well as acromioclavicular arthritis. In addition, rotator cuff atrophy was evaluated by the scapular ratio. Univariate analysis of variance and logistic regression analyses were used to compare demographics and rotator cuff pathology between those with Medicaid and Medicare, as well as between publicly and privately insured patients. Results Of the 492 patients in this study, 192 had private insurance, and 300 had public insurance (Medicaid: 50 and Medicare: 250). Insurance status was not found to be associated with differences in RCTs between Medicare and Medicaid patients. Those with Medicaid or Medicare (public), presented more frequently with SS or IS atrophy (SS atrophy, P = .002; IS atrophy, P = .039) than those with private insurance. However, after adjusting for age, no significant differences in rotator cuff tendon tear or atrophy frequencies were found between insurance groups. Conclusions Patients with private and public insurance tend to present with similar chronicity and magnitude of RCTs. Insurance status does not appear to influence timely access to surgical care for patients with RCTs at an academic medical center.
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Sulkar HJ, Knighton TW, Amoafo L, Aliaj K, Kolz CW, Zhang Y, Hermans T, Henninger HB. In Vitro Simulation of Shoulder Motion Driven by Three-Dimensional Scapular and Humeral Kinematics. J Biomech Eng 2022; 144:051008. [PMID: 34817051 PMCID: PMC8822462 DOI: 10.1115/1.4053099] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 11/12/2021] [Indexed: 11/08/2022]
Abstract
In vitro simulation of three-dimensional (3D) shoulder motion using in vivo kinematics obtained from human subjects allows investigation of clinical conditions in the context of physiologically relevant biomechanics. Herein, we present a framework for laboratory simulation of subject-specific kinematics that combines individual 3D scapular and humeral control in cadavers. The objectives were to: (1) robotically simulate seven healthy subject-specific 3D scapulothoracic and glenohumeral kinematic trajectories in six cadavers, (2) characterize system performance using kinematic orientation accuracy and repeatability, and muscle force repeatability metrics, and (3) analyze effects of input kinematics and cadaver specimen variability. Using an industrial robot to orient the scapula range of motion (ROM), errors with repeatability of ±0.1 mm and <0.5 deg were achieved. Using a custom robot and a trajectory prediction algorithm to orient the humerus relative to the scapula, orientation accuracy for glenohumeral elevation, plane of elevation, and axial rotation of <3 deg mean absolute error (MAE) was achieved. Kinematic accuracy was not affected by varying input kinematics or cadaver specimens. Muscle forces over five repeated setups showed variability typically <33% relative to the overall simulations. Varying cadaver specimens and subject-specific human motions showed effects on muscle forces, illustrating that the system was capable of differentiating changes in forces due to input conditions. The anterior and middle deltoid, specifically, showed notable variations in patterns across the ROM that were affected by subject-specific motion. This machine provides a platform for future laboratory studies to investigate shoulder biomechanics and consider the impacts of variable input kinematics from populations of interest, as they can significantly impact study outputs and resultant conclusions.
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Affiliation(s)
- Hema J. Sulkar
- Department of Orthopaedics, University of Utah, Salt Lake City, UT 84108; Department of Biomedical Engineering, University of Utah, Salt Lake City, UT 84112
| | - Tyler W. Knighton
- Department of Orthopaedics, University of Utah, Salt Lake City, UT 84108; Department of Mechanical Engineering, University of Utah, Salt Lake City, UT 84112
| | - Linda Amoafo
- Department of Epidemiology, University of Utah, Salt Lake City, UT 84132
| | - Klevis Aliaj
- Department of Orthopaedics, University of Utah, Salt Lake City, UT 84108; Department of Biomedical Engineering, University of Utah, Salt Lake City, UT 84112
| | - Christopher W. Kolz
- Department of Orthopaedics, University of Utah, Salt Lake City, UT 84108; Department of Biomedical Engineering, University of Utah, Salt Lake City, UT 84112
| | - Yue Zhang
- Department of Epidemiology, University of Utah, Salt Lake City, UT 84132
| | - Tucker Hermans
- Department of Mechanical Engineering, University of Utah, Salt Lake City, UT 84112; Robotics Center and School of Computing, University of Utah, Salt Lake City, UT 84112
| | - Heath B. Henninger
- Department of Orthopaedics, University of Utah, Salt Lake City, UT 84108; Department of Biomedical Engineering, University of Utah, Salt Lake City, UT 84112; Department of Mechanical Engineering, University of Utah, Salt Lake City, UT 84112
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Pataky J, Seelam V, Engle L, Khandare S, Armstrong AD, Vidt ME. Glenohumeral joint loading is impacted by rotator cuff tear severity during functional task performance. Clin Biomech (Bristol, Avon) 2021; 90:105494. [PMID: 34634580 DOI: 10.1016/j.clinbiomech.2021.105494] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 09/17/2021] [Accepted: 09/21/2021] [Indexed: 02/07/2023]
Abstract
BACKGROUND Rotator cuff tear is a common musculoskeletal injury, negatively affecting shoulder function. Rotator cuff tear severity ranges from small to massive tears, but it is unclear how tear severity affects glenohumeral joint loading and how changes contribute to secondary injury. This study's objective was to determine how glenohumeral joint contact force changes with tear severity during functional task performance using computational models. METHODS Eight models of increasing tear severity were developed, ranging from no rotator cuff tear to massive three-tendon tears. Simulations were performed using models representing increasing tear severity and kinematics for five functional tasks (n = 720 simulations). For each task, magnitude and orientation of peak resultant joint contact force for each tear severity was identified, then compared to the no rotator cuff tear model. FINDINGS For all tasks, compared to the no rotator cuff tear model, joint contact force magnitude decreased 9.5% on average with infraspinatus involvement, then plateaued at 20.8% average decrease with subscapularis involvement. Projected orientation of peak joint contact force vector was located more superior in the glenoid with increased tear severity, with significant changes (p < 0.0003) for all tasks with infraspinatus involvement. INTERPRETATION Decreased magnitude and superior orientation of joint contact force suggest fewer intact muscles contribute to force distribution across the joint, although more work is needed characterizing associated compensation strategies. All force vectors remained oriented within the glenoid rim for all tasks and models, suggesting the system prioritizes joint stability. This work identifies how joint contact force changes with rotator cuff tear severity.
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Affiliation(s)
- Joshua Pataky
- Biomedical Engineering, Pennsylvania State University, University Park, PA, USA
| | - Vijitha Seelam
- Biomedical Engineering, Pennsylvania State University, University Park, PA, USA
| | - Lyndsay Engle
- Biomedical Engineering, Pennsylvania State University, University Park, PA, USA
| | - Sujata Khandare
- Biomedical Engineering, Pennsylvania State University, University Park, PA, USA
| | - April D Armstrong
- Orthopaedics and Rehabilitation, Penn State College of Medicine, Hershey, PA, USA
| | - Meghan E Vidt
- Biomedical Engineering, Pennsylvania State University, University Park, PA, USA; Physical Medicine & Rehabilitation, Penn State College of Medicine, Hershey, PA, USA.
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Huang Y, Ernstbrunner L, Robinson DL, Lee PVS, Ackland DC. Complications of Reverse Total Shoulder Arthroplasty: A Computational Modelling Perspective. J Clin Med 2021; 10:5336. [PMID: 34830616 PMCID: PMC8625535 DOI: 10.3390/jcm10225336] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 11/09/2021] [Accepted: 11/09/2021] [Indexed: 11/29/2022] Open
Abstract
Reverse total shoulder arthroplasty (RTSA) is an established treatment for elderly patients with irreparable rotator cuff tears, complex proximal humerus fractures, and revision arthroplasty; however, with the increasing indications for RTSA over the last decade and younger implant recipients, post-operative complications have become more frequent, which has driven advances in computational modeling and simulation of reverse shoulder biomechanics. The objective of this study was to provide a review of previously published studies that employed computational modeling to investigate complications associated with RTSA. Models and applications were reviewed and categorized into four possible complications that included scapular notching, component loosening, glenohumeral joint instability, and acromial and scapular spine fracture, all of which remain a common cause of significant functional impairment and revision surgery. The computational shoulder modeling studies reviewed were primarily used to investigate the effects of implant design, intraoperative component placement, and surgical technique on postoperative shoulder biomechanics after RTSA, with the findings ultimately used to elucidate and mitigate complications. The most significant challenge associated with the development of computational models is in the encapsulation of patient-specific anatomy and surgical planning. The findings of this review provide a basis for future direction in computational modeling of the reverse shoulder.
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Affiliation(s)
- Yichen Huang
- Department of Biomedical Engineering, University of Melbourne, Parkville, VIC 3010, Australia; (Y.H.); (L.E.); (D.L.R.); (P.V.S.L.)
| | - Lukas Ernstbrunner
- Department of Biomedical Engineering, University of Melbourne, Parkville, VIC 3010, Australia; (Y.H.); (L.E.); (D.L.R.); (P.V.S.L.)
- Department of Orthopaedic Surgery, Royal Melbourne Hospital, Parkville, VIC 3050, Australia
- Melbourne Orthopaedic Group, Windsor, VIC 3181, Australia
| | - Dale L. Robinson
- Department of Biomedical Engineering, University of Melbourne, Parkville, VIC 3010, Australia; (Y.H.); (L.E.); (D.L.R.); (P.V.S.L.)
| | - Peter Vee Sin Lee
- Department of Biomedical Engineering, University of Melbourne, Parkville, VIC 3010, Australia; (Y.H.); (L.E.); (D.L.R.); (P.V.S.L.)
| | - David C. Ackland
- Department of Biomedical Engineering, University of Melbourne, Parkville, VIC 3010, Australia; (Y.H.); (L.E.); (D.L.R.); (P.V.S.L.)
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Goetti P, Denard PJ, Collin P, Ibrahim M, Mazzolari A, Lädermann A. Biomechanics of anatomic and reverse shoulder arthroplasty. EFORT Open Rev 2021; 6:918-931. [PMID: 34760291 PMCID: PMC8559568 DOI: 10.1302/2058-5241.6.210014] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The biomechanics of the shoulder relies on careful balancing between stability and mobility. A thorough understanding of normal and degenerative shoulder anatomy is necessary, as the goal of anatomic total shoulder arthroplasty is to reproduce premorbid shoulder kinematics.With reported joint reaction forces up to 2.4 times bodyweight, failure to restore anatomy and therefore provide a stable fulcrum will result in early implant failure secondary to glenoid loosening.The high variability of proximal humeral anatomy can be addressed with modular stems or stemless humeral components. The development of three-dimensional planning has led to a better understanding of the complex nature of glenoid bone deformity in eccentric osteoarthritis.The treatment of cuff tear arthropathy patients was revolutionized by the arrival of Grammont's reverse shoulder arthroplasty. The initial design medialized the centre of rotation and distalized the humerus, allowing up to a 42% increase in the deltoid moment arm.More modern reverse designs have maintained the element of restored stability but sought a more anatomic postoperative position to minimize complications and maximize rotational range of motion. Cite this article: EFORT Open Rev 2021;6:918-931. DOI: 10.1302/2058-5241.6.210014.
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Affiliation(s)
- Patrick Goetti
- Division of Orthopaedics and Trauma Surgery, Centre Hospitalier |Universitaire Vaudois, Lausanne, Switzerland
| | - Patrick J. Denard
- Denard Department of Orthopaedic & Rehabilitation, Oregon Health & Science University, Portland, Oregon, United States
| | - Philippe Collin
- Collin Centre Hospitalier Privé Saint-Grégoire (Vivalto Santé), Saint- Grégoire, France
| | - Mohamed Ibrahim
- Mohamed Ibrahim, Department of Orthopaedics and Trauma Surgery, Faculty of Medicine, Fayoum University, Fayoum, Egypt
| | - Adrien Mazzolari
- Division of Orthopaedics and Trauma Surgery, La Tour Hospital, Meyrin, Switzerland
| | - Alexandre Lädermann
- Division of Orthopaedics and Trauma Surgery, La Tour Hospital, Meyrin, Switzerland
- Division of Orthopaedics and Trauma Surgery, Department of Surgery, Geneva University Hospitals, Geneva, Switzerland
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Chen Z, Fan X, Gao Y, Zhang J, Guo L, Chen S, Jin Z. Effect of Rotator Cuff Deficiencies on Muscle Forces and Glenohumeral Contact Force After Anatomic Total Shoulder Arthroplasty Using Musculoskeletal Multibody Dynamics Simulation. Front Bioeng Biotechnol 2021; 9:691450. [PMID: 34291041 PMCID: PMC8287529 DOI: 10.3389/fbioe.2021.691450] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 06/11/2021] [Indexed: 11/13/2022] Open
Abstract
Anatomic total shoulder arthroplasty (ATSA) is widely used to treat the diseases of the glenohumeral (GH) joint. However, the incidence of rotator cuff tears after ATSA increases during follow-up. The effects of rotator cuff deficiencies after ATSA on the biomechanics of the GH joint are to be investigated. In this study, a musculoskeletal multibody dynamics model of ATSA was established using a force-dependent kinematics (FDK) method. The biomechanical effects were predicted during arm abduction under different rotator cuff deficiencies. The deltoid forces were increased under the rotator cuff deficiencies, the maximum deltoid forces were increased by 36% under the subscapularis deficiency and by 53% under the supraspinatus, infraspinatus, subscapularis, and teres minor deficiencies. The maximum GH contact forces were decreased by 11.3% under supraspinatus and infraspinatus deficiencies but increased by 24.8% under subscapularis deficiency. The maximum subscapularis force was decreased by 17% under only infraspinatus tear during arm abduction. The results suggested that the changes in the biomechanics of the GH joint induced by rotator cuff deficiencies after ATSA increase the deltoid muscle energy expenditure and joint instability, which result in postoperative less satisfactory clinical outcomes. The changes in rotator cuff muscle forces deserve more attention for understanding the evolution of rotator cuff tear after ATSA.
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Affiliation(s)
- Zhenxian Chen
- Key Laboratory of Road Construction Technology and Equipment of MOE, Chang'an University, Xi'an, China
| | - Xunjian Fan
- Institute of Mechanical Manufacturing Technology, China Academy of Engineering Physics, Mianyang, China
| | - Yongchang Gao
- Key Laboratory of Road Construction Technology and Equipment of MOE, Chang'an University, Xi'an, China
| | - Jing Zhang
- Key Laboratory of Road Construction Technology and Equipment of MOE, Chang'an University, Xi'an, China
| | - Lei Guo
- Key Laboratory of Road Construction Technology and Equipment of MOE, Chang'an University, Xi'an, China
| | - Shibin Chen
- Key Laboratory of Road Construction Technology and Equipment of MOE, Chang'an University, Xi'an, China
| | - Zhongmin Jin
- State Key Laboratory for Manufacturing Systems Engineering, School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an, China.,Institute of Medical and Biological Engineering, School of Mechanical Engineering, University of Leeds, Leeds, United Kingdom.,Tribology Research Institute, School of Mechanical Engineering, Southwest Jiaotong University, Chengdu, China
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12
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Evaluation of rotator cuff abduction moment arms for superior capsular reconstruction and reverse total shoulder arthroplasty. INTERNATIONAL ORTHOPAEDICS 2021; 45:1767-1774. [PMID: 34027565 DOI: 10.1007/s00264-021-05066-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Accepted: 04/26/2021] [Indexed: 11/27/2022]
Abstract
PURPOSE The rotator cuff (RC) muscles contribute to dynamic stability and rotational actions of the glenohumeral joint. Moment arm can be used to demonstrate the potential work a muscle contributes to a musculoskeletal joint rotation. This study aimed to understand the moment arm contributions of the RC muscles and explore changes following a complete supraspinatus tear treated with either superior capsular reconstruction (SCR) or reverse total shoulder arthroplasty (rTSA). METHODS Five fresh-frozen cadaveric specimens were prepared and mounted in an apparatus where each intact RC muscle was held in tension with a line of action toward its origin on the scapula. Mean moment arms for each muscle were determined experimentally based on Optotrak data collected during cadaveric shoulder arm abduction. RESULTS Using ANOVA testing, our analysis demonstrated significant differences (p < 0.001) in infraspinatus and teres minor moment arms after rTSA compared to the intact shoulder model. After SCR, significant differences (p < 0.001) were seen in teres minor, with these differences being statistically similar to the changes seen in teres minor after rTSA. Subscapularis showed no significant difference in moment arm values between the models (p = 0.148). CONCLUSION Our results illustrate that mean moment arms were preserved in the RC muscles after complete supraspinatus tear. This study also shows evidence that subscapularis function may be maintained after SCR or rTSA. After SCR, infraspinatus may maintain similar abduction ability compared to the anatomical shoulder, while teres minor ability may increase. Infraspinatus may have decreased abduction ability after rTSA while teres minor may have increased ability.
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Hochreiter B, Hasler A, Hasler J, Kriechling P, Borbas P, Gerber C. Factors influencing functional internal rotation after reverse total shoulder arthroplasty. JSES Int 2021; 5:679-687. [PMID: 34223415 PMCID: PMC8245997 DOI: 10.1016/j.jseint.2021.03.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Background Functional internal rotation (fIR) of the shoulder is frequently limited after reverse shoulder arthroplasty (RTSA). The objective of this study was to study a cohort of satisfied patients after RTSA who had comparable active mobility except for fIR and to identify factors associated with selective loss of fIR. Methods A retrospective cohort study was conducted to compare 2 patient groups with either poor (≤ 2 points in the Constant-Murley score [CS]) or excellent (≥8 points in CS) fIR after RTSA at a minimum follow-up of 2 years. Influencing factors (demographic, surgical or implant related, radiographic parameters) and clinical outcome were analyzed. Results Fifty-two patients with a mean age of 72.8 (±9.3) and a mean follow-up of 41 months were included in the IR≤2 group and 63 patients with a mean age of 72.1 (±8.0) and a mean follow-up of 59 months in the IR≥8 group. All patients had undergone RTSA with the same implant type and only 2 different glenosphere sizes (36 and 40) for comparable indications. A multivariate analysis identified the following significant risk factors for poor postoperative fIR: poor preoperative fIR (pts in CS: 3 [range: 2-6] vs. 6 [range: 4-8], P<.0001), smoking (17.3% vs. 6.5%, P = .004), male gender (59.6% vs. 31.7%, P = .002), less preoperative to postoperative distalization of the greater tuberosity (Δ 19.4 mm vs. 22.2 mm, P = .026), a thin humeral insert (≤3 mm: 23.1% vs. 54.8%, P = .039), and a high American Society of Anesthesiologists score (≤ III: 30.8% vs. 14.3%, P = .043). Subscapularis repair status and glenosphere size had no influence on fIR. Clinical outcome scores improved in both groups from preoperatively to last follow-up. The IR≥8 group had overall significantly better outcome scores compared to the IR≤2 group (Δ 9.3% SSV and Δ 9.5% relative CS, P < .0001). There was no difference in CS between the cohorts when the score for fIR was discarded. Conclusion Independent risk factors for poor postoperative fIR after RTSA are poor preoperative fIR, smoking, male gender, less preoperative to postoperative distalization of the greater tuberosity, a thin humeral insert height, and a high American Society of Anesthesiologists score. Except for male gender, these factors are modifiable. These findings may be a valuable addition to patient counselling as well as preoperative planning and preoperative and intraoperative decision-making. The relevance of fIR for overall satisfaction is substantiated by this study.
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Affiliation(s)
- Bettina Hochreiter
- Department of Orthopaedics, Balgrist University Hospital, University of Zürich, Zürich, Switzerland
| | - Anita Hasler
- Department of Orthopaedics, Balgrist University Hospital, University of Zürich, Zürich, Switzerland
| | - Julian Hasler
- Department of Orthopaedics, Balgrist University Hospital, University of Zürich, Zürich, Switzerland
| | - Philipp Kriechling
- Department of Orthopaedics, Balgrist University Hospital, University of Zürich, Zürich, Switzerland
| | - Paul Borbas
- Department of Orthopaedics, Balgrist University Hospital, University of Zürich, Zürich, Switzerland
| | - Christian Gerber
- Department of Orthopaedics, Balgrist University Hospital, University of Zürich, Zürich, Switzerland
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Allograft-Composite Reverse Shoulder Arthroplasty for Malignant Tumor of the Proximal Humerus. Tech Hand Up Extrem Surg 2020; 25:94-101. [PMID: 33044287 DOI: 10.1097/bth.0000000000000318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Composite-allograft reverse shoulder arthroplasties are a surgical alternative in malignant tumor reconstructions following segmental bone resection of the proximal humerus. They allow reinsertion of the rotator cuff tendons and reliable restoration of humeral height, increasing prosthetic stability and mobility. Preoperative local tumor extension assessment must be thorough and a strict surgical technique must be followed to obtain satisfactory functional results. The indications for this procedure include a strictly intraosseous tumor of the proximal humerus corresponding to an S3-S4 A resection following criteria provided by the Musculoskeletal Tumor Society as described by Enneking and colleagues in 1990. Certain conditions must question the procedure such as extended S3-S4-S5 bone resections, partial sacrifice of the deltoid muscle, preoperative deltoid impairment, and glenohumeral arthrectomy. Here, we report technical details and indications of composite-allograft reverse shoulder arthroplasty in the context of tumor segmental resection of the proximal humerus, especially in the humeral preparation.
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Reilly M, Kontson K. Computational musculoskeletal modeling of compensatory movements in the upper limb. J Biomech 2020; 108:109843. [PMID: 32635990 DOI: 10.1016/j.jbiomech.2020.109843] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 05/07/2020] [Accepted: 05/09/2020] [Indexed: 11/26/2022]
Abstract
It is well documented that most upper limb amputees utilize compensatory movement strategies to accomplish everyday tasks when using a prosthetic device and that musculoskeletal complaints (MSCs) are more common in this population. However, little information is available on how the loss of distal degrees of freedom (DOFs) in the arm impact muscle force, thereby limiting our understanding of the mechanism by which these MSCs are manifesting. Knowledge of how a loss of DOFs may lead to MSCs can enable clinicians to provide more targeted guidance on how best to restore functional ability while addressing pain, and may serve as a tool for prescriptive decision-making when determining the impact of device selection on long-term clinical needs. 3D motion capture data were collected from 12 right-handed subjects with no upper limb disability using an 8-camera Vicon™ motion analysis system as they performed the targeted Box and Blocks test under normal and braced conditions to simulate a loss of DOFs in the wrist and fingers. Muscle force data were calculated using AnyBody Modeling Software™ for four different muscles: erector spinae, infraspinatus, deltoid, and trapezius. Linear mixed effects models were generated using the peak force data and mean force data for a given muscle fascicle. The fixed effect coefficient and 95% confidence intervals were reported for each muscle fascicle. Overall, a strong effect of condition on muscle force was seen for most muscles in the right side of the body (specifically deltoid and infraspinatus), with greater forces generated during the braced condition.
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Affiliation(s)
- Michael Reilly
- U.S. FDA, Center for Devices and Radiological Health, Office of Science and Engineering Labs, Division of Biomedical Physics, Silver Spring, MD, United States
| | - Kimberly Kontson
- U.S. FDA, Center for Devices and Radiological Health, Office of Science and Engineering Labs, Division of Biomedical Physics, Silver Spring, MD, United States.
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16
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Williamson PM, Hanna P, Momenzadeh K, Lechtig A, Okajima S, Ramappa AJ, DeAngelis JP, Nazarian A. Effect of rotator cuff muscle activation on glenohumeral kinematics: A cadaveric study. J Biomech 2020; 105:109798. [PMID: 32423544 DOI: 10.1016/j.jbiomech.2020.109798] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 04/10/2020] [Accepted: 04/14/2020] [Indexed: 12/20/2022]
Abstract
Healthy shoulder function requires the coordination of the rotator cuff muscles to maintain the humeral head's position in the glenoid. While glenohumeral stability has been studied in various settings, few studies have characterized the effect of dynamic rotator cuff muscle loading on glenohumeral translation during shoulder motion. We hypothesize that dynamic rotator cuff muscle activation decreases joint translation during continuous passive abduction of the humerus in a cadaveric model of scapular plane glenohumeral abduction. The effect of different rotator cuff muscle activity on glenohumeral translation was assessed using a validated shoulder testing system. The Dynamic Load profile is a novel approach, based on musculoskeletal modeling of human subject motion. Passive humeral elevation in the scapular plane was applied via the testing system arm, while the rotator cuff muscles were activated according to the specified force profiles using stepper motors and a proportional control feedback loop. Glenohumeral translation was defined according to the International Society of Biomechanics. The Dynamic load profile minimized superior translation of the humeral head relative to the conventional loading profiles. The total magnitude of translation was not significantly different (0.805) among the loading profiles suggesting that the compressive forces from the rotator cuff primarily alter the direction of humeral head translation, not the magnitude. Rotator cuff muscle loading is an important element of cadaveric shoulder studies that must be considered to accurately simulate glenohumeral motion. A rotator cuff muscle activity profile based on human subject muscle activity reduces superior glenohumeral translation when compared to previous RC loading profiles.
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Affiliation(s)
- Patrick M Williamson
- Boston University, Mechanical Engineering Department, Boston, MA, USA; Center for Advanced Orthopaedic Studies at Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Philip Hanna
- Center for Advanced Orthopaedic Studies at Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Kaveh Momenzadeh
- Center for Advanced Orthopaedic Studies at Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Aron Lechtig
- Center for Advanced Orthopaedic Studies at Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Stephen Okajima
- Center for Advanced Orthopaedic Studies at Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Arun J Ramappa
- Center for Advanced Orthopaedic Studies at Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA; Carl J. Shapiro Department of Orthopaedic Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Joseph P DeAngelis
- Center for Advanced Orthopaedic Studies at Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA; Carl J. Shapiro Department of Orthopaedic Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Ara Nazarian
- Center for Advanced Orthopaedic Studies at Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA; Carl J. Shapiro Department of Orthopaedic Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA; Department of Orthopaedic Surgery, Yerevan State Medical University, Yerevan, Armenia.
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Rienmüller A, Maffiuletti NA, Schwyzer HK, Eggspühler A. Shoulder Muscle Strength and Neuromuscular Activation 2 Years after Reverse Shoulder Prosthesis-An Experimental Case Control Study. J Clin Med 2020; 9:jcm9020365. [PMID: 32013074 PMCID: PMC7073832 DOI: 10.3390/jcm9020365] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 01/24/2020] [Accepted: 01/27/2020] [Indexed: 11/17/2022] Open
Abstract
Although reverse shoulder arthroplasty (RSA) has shown successful postoperative outcomes, little is known about compensatory activation patterns of remaining shoulder muscles following RSA. The purpose of this experimental case control series was to investigate shoulder muscle strength and neuromuscular activation of deltoid and teres minor muscles 2 years after RSA. Humerus lengthening, center-of-rotation medialization, maximal voluntary strength, and electromyographic (EMG) activity were compared between the operated and the non-operated side of 13 patients (mean age: 73 years). Shoulder muscle strength was significantly lower on the operated side for external rotation (−54%), internal rotation (−20%), and adduction (−13%). Agonist deltoid EMG activity was lower on the operated side for shoulder flexion, extension, and internal and external rotation (p < 0.05). Antagonist deltoid coactivation was higher on the operated side for external rotation (p < 0.001). Large correlation coefficients were observed between shoulder adductor strength asymmetry and both center-of-rotation medialization (r = −0.73) and humerus lengthening (r = 0.71). Shoulder abduction strength and neuromuscular activation were well preserved 2 years after RSA, while persistent strength and activation deficits were observed for shoulder adduction and internal and external rotation. Additional studies are required to elucidate shoulder neuromuscular activation patterns before and after RSA to support decision making for surgical, implant design, and rehabilitation choices.
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Affiliation(s)
- Anna Rienmüller
- Department of Orthopedic and Trauma Surgery, Medical University Vienna, AT-1090 Vienna, Austria
- Correspondence:
| | | | - Hans-Kaspar Schwyzer
- Department of Orthopedic Surgery, Schulthess Clinic, CH-8008 Zurich, Switzerland;
| | - Andreas Eggspühler
- Department of Neurology, Schulthess Clinic, CH-8008 Zurich, Switzerland;
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Ackland DC, Wu W, Thomas R, Patel M, Page R, Sangeux M, Richardson M. Muscle and Joint Function After Anatomic and Reverse Total Shoulder Arthroplasty Using a Modular Shoulder Prosthesis. J Orthop Res 2019; 37:1988-2003. [PMID: 31041997 DOI: 10.1002/jor.24335] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 04/23/2019] [Indexed: 02/04/2023]
Abstract
Changes in joint architecture and muscle loading resulting from total shoulder arthroplasty (TSA) and reverse total shoulder arthroplasty (RSA) are known to influence joint stability and prosthesis survivorship. This study aimed to measure changes in muscle moment arms, muscle lines of action, as well as muscle and joint loading following TSA and RSA using a metal-backed uncemented modular shoulder prosthesis. Eight cadaveric upper extremities were assessed using a customized testing rig. Abduction, flexion, and axial rotation muscle moment arms were quantified using the tendon-excursion method, and muscle line-of-force directions evaluated radiographically pre-operatively, and after TSA and revision RSA. Specimen-specific musculoskeletal models were used to estimate muscle and joint loading pre- and post-operatively. TSA lateralized the glenohumeral joint center by 4.3 ± 3.2 mm, resulting in small but significant increases in middle deltoid force (2.0%BW) and joint compression during flexion (2.1%BW) (p < 0.05). Revision RSA significantly increased the moment arms of the major abductors, flexors, adductors, and extensors, and reduced their peak forces (p < 0.05). The superior inclination of the deltoid significantly increased while the inferior inclination of the rotator cuff muscles decreased (p < 0.05). TSA using an uncemented metal-backed modular shoulder prosthesis effectively restores native joint function; however, lateralization of the glenoid component should be minimized intra-operatively to mitigate increased glenohumeral joint loading and polyethylene liner contact stresses. Revision RSA reduces muscle forces required during shoulder function but produces greater superior joint shear force and less joint compression. The findings may help to guide component selection and placement to mitigate joint instability after arthroplasty. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1988-2003, 2019.
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Affiliation(s)
- David C Ackland
- Department of Biomedical Engineering, University of Melbourne, Parkville, Victoria, Australia
| | - Wen Wu
- Department of Biomedical Engineering, University of Melbourne, Parkville, Victoria, Australia
| | - Richard Thomas
- Department of Biomedical Engineering, University of Melbourne, Parkville, Victoria, Australia
| | - Minoo Patel
- Department of Orthopaedic Surgery, Epworth Healthcare, Richmond, Victoria, Australia
| | - Richard Page
- Department of Orthopaedic Surgery, Barwon Health, Geelong, Victoria, Australia.,School of Medicine, Barwon Centre for Orthopaedic Research and Education, Deakin University, Geelong, Victoria, Australia
| | - Morgan Sangeux
- Murdoch Children's Research Institute, Parkville, Victoria, Australia
| | - Martin Richardson
- Department of Orthopaedic Surgery, Epworth Healthcare, Richmond, Victoria, Australia
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